function isValidUrl(url) {
    return /(ht|f)tp(s?):\/\/([^ \\/]*\.)+[^ \\/]*(:[0-9]+)?\/?/.test(url);
  }
  
  /**
   * 深度对比两个对象是否一致
   * from: https://github.com/epoberezkin/fast-deep-equal
   * @param  {Object} a 对象a
   * @param  {Object} b 对象b
   * @return {Boolean}   是否相同
   */
  /* eslint-disable */
  function equal(a, b) {
    if (a === b) return true;
  
    if (a && b && typeof a == 'object' && typeof b == 'object') {
      var arrA = Array.isArray(a)
        , arrB = Array.isArray(b)
        , i
        , length
        , key;
  
      if (arrA && arrB) {
        length = a.length;
        if (length != b.length) return false;
        for (i = length; i-- !== 0;)
          if (!equal(a[i], b[i])) return false;
        return true;
      }
  
      if (arrA != arrB) return false;
  
      var dateA = a instanceof Date
        , dateB = b instanceof Date;
      if (dateA != dateB) return false;
      if (dateA && dateB) return a.getTime() == b.getTime();
  
      var regexpA = a instanceof RegExp
        , regexpB = b instanceof RegExp;
      if (regexpA != regexpB) return false;
      if (regexpA && regexpB) return a.toString() == b.toString();
  
      var keys = Object.keys(a);
      length = keys.length;
  
      if (length !== Object.keys(b).length)
        return false;
  
      for (i = length; i-- !== 0;)
        if (!Object.prototype.hasOwnProperty.call(b, keys[i])) return false;
  
      for (i = length; i-- !== 0;) {
        key = keys[i];
        if (!equal(a[key], b[key])) return false;
      }
  
      return true;
    }
  
    return a!==a && b!==b;
  }
  
  module.exports = {
    isValidUrl,
    equal
  };